With the progressive growing of the fiber optic communication techniques, the wavelength division multiplexing (WDM) optical transmission systems are increasingly deployed. With the wavelength division multiplexing technique, a plurality of optical signals having different wavelengths are multiplexed into one (wavelength division multiplexed) signal for transmission through the optical fiber, improving the transmission bandwidth of the communication network effectively.
Referring to FIG. 1, a schematic block diagram of a transmitting device in a wavelength division multiplexing optical transmission system of the prior art is illustrated. The transmitting device includes a plurality of optical interfaces 11, a plurality of electro-optic conversion modules 12 for performing electro-optic conversions on the various electric signals, and a multiplexer 13 for wavelength division multiplexing the optical signals of various wavelengths from the electro-optic conversion modules 12 into one optical signal. Each optical interface 11 couples an optical signal to the multiplexer 13 via a corresponding fiber optic patch cord.
Referring to FIG. 2, a schematic block diagram of a receiving device in a wavelength division multiplexing optical transmission system in the prior art is illustrated. The receiving device includes a demultiplexer 21 for demultiplexing the wavelength division multiplexed signal to be converted into various wavelength optical signals, a plurality of optical interfaces 22, and a plurality of optic-electro conversion modules 23 for converting the various wavelength optical signals into electric signals. The demultiplexer couples each optical signal to an optical interface 22 via a corresponding fiber optic patch cord.
In the above wavelength division multiplexing system in the prior art, for the electric signals to be converted, a corresponding number of optical interfaces and optic modules are required in the transmitting device to achieve the electro-optic conversions for the various electric signals to be converted; and for the optical signals to be converted, a corresponding number of optical interfaces and optic modules are also required in the receiving device to achieve the optic-electro conversions for the various optical signals to be converted. Generally, a great number of electric signal conversions or optical signal conversions are required in the transmitting and receiving devices of the wavelength division multiplexing system. Therefore, a large number of optical interfaces and optic modules are required in the transmitting or receiving device of the wavelength division multiplexing system in the prior art to achieve the corresponding electro-optic conversions or optic-electro conversions, so that the transmitting or receiving device has a large volume, much internal fiber optic patch cord data and complex connections, thereby being impedimental to improving the integrity of the devices, reducing the power consumption of the devices, or simplifying the operation or maintenance.